Down-hole sample chamber



0 14, 1958 R. w. BECK 2,856,005

DOWN-HOLE SAMPLE CHAMBER Filed Aug 28, 1956 2 WIRE LINE 3 O'VERSHQT GRAB 4 TUBING COLLAR 5 WRENCH FLAT SPRING TYPE STOPS 25 COLLAR LOCATOR 25 7 SAMPLE TUBE a spam CENTRALIZER SPRINGDOG IO WRENCH FLAT I! RING END I CASING l2 RING END 28 WRENCH FLAT 4 BOTTOM SAMPLE TUBE VALVE l5 WRENCH FLAT WEIGHT United dttes Patent DOWN-HOLE SAMPLE CHAMBER Robert W. Beck, Caracas, Venezuela, assignor, by mesne assignments, to Jersey Production Research Company Application August 28, 1956, Serial No. 606,714

Claims. (Cl. 166162) The present invention is concerned with an apparatus and method for obtaining representative fluid samples from subterranean formations. It i more particularly concerned with an improved sampling chamber whereby a fluid or semi-fluid sample may be readily obtained and wherein the sample accurately represents the bore hole fluid being sampled.

A series and important problem that confronts the petroleum producing industry at the present time is one of obtaining reliable samples of petroliferous formations and fluids that lie beneath the surface of the earth. The problem has become one of particular importance in view of the ever increasing use of secondary recovery methods for obtaining additional oil from subterranean oil reservoirs that have ceased primary production. It is essential, before initiating a secondary recovery procedure in any such reservoir, to have as much information as possible about the structure, the fluid content, the pore volume, the permeability, etc. of the formation. Such information is extremely valuable in determining whether the formation is susceptible to successful exploitation using secondary recovery techniques and just which techniques should preferentially be utilized.

In line with the growing emphasis on secondary recovery programs, many petroleum producers are conducting extensive analyses of old reservoirs and fields that have in years past lost their reservoir pressure and been abandoned. In an efiort to evaluate these old reservoirs and fields and in order to determine whether a secondary recovery procedure can be successfully applied to them,

the producers are conducting extensive sampling programs.

The apparatus of the present invention whereby representative fluid samples are obtained may be fully understood by reference to the drawing illustrating an embodiment of the same. Referring specifically to the drawing, the sampling assembly is shown disposed in casing 1 extending below the earths surface. The sampling as sembly may be lowered or raised by means of a Wire line 2 in conjunction with an overshot grab 3. The sample chamber 7 is positioned at the desired location in the casing by means of spring type lockers 6 which seat themselves in a recess of tubing collar 4. These lockers may be of the type whereby a second overshot will retract and release them, or they may be replaceable. Under such conditions an added increment pull from the surface will bend them thereby releasing the assembly. The sample tube 7 is centrally positioned in casing 1 by means of spring centralizer 8. The piston element which comprises an upper ring and seals 11 and a lower ring seals 12 is raised into the sample tube by means of wire line from the surface. Thus, as the piston "ice element is moved upwardly in the sample tube, a representative sample will be secured between the respective end seals and the walls of the sample tube. The entire assembly is then raised to the surface at which time the assembly can be removed from the cable by means of a wrench flat 5 and the weight section 16 removed from the sample by means of a wrench flat 15. The removal of the sample from the sample chamber can be secured either by removing it from a bottom sample tube valve 14 or upper sample tube valve.

Thus, the sample is contained between the walls of the tube and the upper and lower piston heads of the piston element. Fluid flow by the respective piston heads is prevented by the end seals.

Additional upward force is then applied to the wire line, causing the replaceable springs to buckle and permitting the withdrawal of the entire assembly to the surface. As pointed out heretofore, the seating springs 6 may be replaceable as illustrated in the drawing or may be of the type wherein a second overshot may be positioned so as to retract them.

The apparatus of the present invention permits the sampling of a fluid or semi-fluid in the environment without undue disturbance, thereby securing an accurate sample of the environment.

What is claimed is:

1. Improved sample chamber for securing a representative fluid sample from a well bore hole which comprises a cylindrical element having attached thereto seating means for positioning said cylindrical element at a predetermined point in a bore hole, a piston element assembly which is slidably movable with respect to said cylindrical element when said cylindrical element is seated, said piston element being characterized by having an upper head section and a lower head section whereby when said piston element is lowered with respect to said cylindrical element and then raised with respect to said cylindrical element, a fluid sample will be contained within said head sections of said piston element and the inner wall of said cylindrical element of said sample tube.

2. Apparatus as defined by claim 1 wherein said head sections contain conduits controlled by valve means, thus permitting the efiicient removal of the sample from said sample tube.

3. Apparatus as defined by claim 2 wherein there is attached a weight section at the lower end of said piston element which will cause said piston element to move downwardly with respect to said sample tube when said sample tube is seated.

4. Apparatus as defined by claim 3 wherein said piston element contains stops which seat themselves on the top of said sample tube thereby preventing any further movement downwardly of said piston element with respect to said sample tube.

5. Apparatus as defined by claim 4 wherein said sample tube contains shoulder elements which seat themselves on the top of said upper head section thereby preventing any further upward movement of said piston element with respect to said sample tube.

Johnson Apr. 7, 1931 Lindsly Dec. 28, 1937 

